If I rememeber correctly, in Korea medevac helicopters were marked as per the international conventions (Geneva or Hague, not exactly sure) and they still took

If I rememeber correctly, in Korea medevac helicopters were marked as per the international conventions (Geneva or Hague, not exactly sure) and they still took fire anyways. Also, there's another issue that won't and can't be mitigated by any visual means, many aerial engagements on a peer to peer conflict happen outside of visual range and on that case any non visual IFF would have to be radio based and due to the inherent proximity of medevac missions to the forward line of contact would be very susceptible to electronic warfare. So I'd argue that red crosses on front line medevac helicopters aren't that important